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Lattice Points of Cut Cones

Published online by Cambridge University Press:  12 September 2008

Michel Deza
Affiliation:
CNRS-LIENS, Ecole Normale Supérieure, Paris
Viatcheslav Grishukhin
Affiliation:
Central Economic and Mathematical Institute of Russian Academy of Sciences (CEMI RAN), Moscow

Abstract

Let ℝ+(ℋn),ℤ(ℋn),ℤ+(ℋn) be, respectively, the cone over ℝ, the lattice and the cone over ℤ, generated by all cuts of the complete graph on n nodes. For i ≥ 0, let has exactly i realizations in ℤ+(ℋn)}. We show that is infinite, except for the undecided case and empty and for i = 0, n ≤ 5 and for i ≥ 2, n ≤ 3. The set contains 0,1,∞ nonsimplicial points for n ≤ 4, n = 5, n ≥ 6, respectively. On the other hand, there exists a finite number t(n) such that t(n)d ∈ ℤ+(ℋn) for any ; we also estimate such scales for classes of points. We construct families of points of and ℤ+(ℋn), especially on a 0-lifting of a simplicial facet, and points d ∈ ℝ+(ℋn) with di, n = t for 1 ≤ in − 1.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1994

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